I received my Brembo calipers back from Mike the Powder coater (nice work).

I placed the Hawk high performance street pads (thanks Sleez) in them for a test fit.

It appears the bigger piston on the front Brembo calipers would not be completely seated against the back of the pad. This is due to the edge of the metal plate on the back of the pad stopping before the pad edge.

So it appears the plates/shims (#2 above) might also distribute the piston force more evenly besides reducing noise.

So for those of you with Hawk HPS pads, did you reuse the Brembo plates/shims with the Hawk pads or leave them out?

Another way to ask this question. Do replacement GM pads come with new plates/shims or are they considered part of the caliper?

Shims, when they are used, always come with the pads for which they were intended. I guess the short answer to your question is they are part of the pad, not the caliper. And yes, they are usually built into the pad.

It appears the bigger piston on the front Brembo calipers would not be completely seated against the back of the pad. This is due to the edge of the metal plate on the back of the pad stopping before the pad edge.?

Install planned for this weekend (UPS willing). I'll take pics and post then.

It's just Hawk HPS pads on Brembo Calipers though.

I understand it should be straight forward, but if the backing plate and the large front piston don't line up you should not install them. These brake pads overheated, but they show piston placement well. Your backing plate should line up the same way.